Energetic considerations for the photoisomerization of vinyl cinnamates

Preparation and Photochemistry of 3-O-Methylestra-1,3,5(10)-Triene-17beta-yl Cinnamates and 3-O-Methylestra-1,3,5(10)-Trien-17-one O-Cinnamoyl-17-Oximes

“…Computational studies on the photoisomerization of cinnamates have been carried out previously by other groups. 16 It has been noted that the photoisomerization is affected by the substitution in the aromatic system. 17,18 From the experimental results, it was evident that 4-methoxycinnamate E-2a and 3,4-dimethoxycinnamate E-2b undergo rapid isomerization at λ = 254 nm, while 2,5-dimethoxycinnamate E-2c does not.…”